US20070049959A1 - Device for sampling blood - Google Patents

Abstract

A blood sampling device includes a lancet having a skin piercing member disposed at an end thereof. The lancet is slidable within and releasably engaged with an elongated lancet guide that remains stationary with use of the device. A shell is axially movable relative to the lancet guide between a rest position and an actuate position, with the lancet being spring loaded within the lancet guide by movement of the shell from the rest position to the actuate position.

Description

BACKGROUND OF THE INVENTION
• Many health care tests (e.g., cholesterol, glucose, etc.) require a blood sample as the source of the analyte. Typically, the blood is withdrawn via an intravenous cannula or syringe wherein a vacuum tube is used to withdrawn and store the blood. This method, however, is not well suited for all individuals, particularly infants, elderly individuals, or ill individuals who cannot afford or are physically incapable of furnishing the required amount of blood. Also, many blood tests do not require the relatively large amount of blood withdrawn via the intravenous method.
• As a result, blood lancets have been developed for withdrawing capillary blood, usually from an individual's fingertip (the “finger prick” method). These devices are more cost effective and generally less traumatic to the individual in obtaining blood samples of up to about 50 microliters. Conventional lancets typically employ a needle or blade at the end of an elongated rigid member that is essentially jabbed into the fingertip by a technician. A vial or blood blotter is then used to collect the blood. However, this procedure also has drawbacks. A successful blood sample depends in large part on the skill of the technician, who must hold the individual's hand and finger steady while accurately “aiming” the lancet and reassuring the patient. The patient's anxiety level can increase rapidly with failed attempts.
• Various spring loaded sampling devices have also been developed, particularly for home diagnostic test kits. Reference is made, for example, to U.S. Pat. Nos. 4,503,856; 4,517,978; and 5,487,748. Spring-loaded devices, however, may have a tendency to prematurely actuate, for example when the individual removes the safety cap. Another common failure occurs when, by reflex, the individual pulls back from the lancet just prior to the device being triggered. This results in a grazing nick to the skin, or no skin penetration at all.
• With growing demand by consumers, and emphasis by healthcare institutions for individuals to participate in and manage aspects of their own health care, home diagnostic test kits have become increasingly important. The blood sampling devices used with these diagnostic test kits play a significant role in the kit's reliability, accuracy, and acceptance by the consuming public. Thus, a continuous need exists in the art for improved blood sampling devices.
SUMMARY
• Objects and advantages of the invention will be set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.
• The present invention is directed generally to a single-use, disposable blood sampling device. The device is particularly suited for home diagnostic test kits, but is not limited to such use. Additionally, the device is not limited to any particular diagnostic test or protocol. The inventive blood sampling device has usefulness in any procedure where blood must be withdrawn from an individual for any reason.
• The present sampling device is also not limited to any particular sampling site on an individual. Fingertip sampling is relatively painful for certain individuals and Alternate Site Testing (AST) is a concept gaining recognition in the medical arts as a preferred method of blood sampling in that it significantly reduces pain and anxiety while reliably producing a sufficient volume of blood for various tests. The sampling device according to the invention is well suited for fingertip sampling as well as AST procedures.
• In particular embodiments, a blood sampling device in accordance with the invention includes a lancet having a skin piercing member, such as a blade or needle, disposed at an end thereof. The lancet is disposed within and axially movable relative to an elongated lancet guide. The lancet is releasably engaged with the lancet guide and is released upon actuation of the device, wherein the lancet is propelled through the lancet guide. The lancet guide has a longitudinal end that is placed against the user's skin. This end may include a recessed skin engagement area such that a portion of the user's skin is caused to bulge into the recessed area when the lancet guide is pressed against the skin.
• The opposite end of the lancet guide is disposed at least partially within a shell. In operation, the lancet guide is pressed against the user's skin and the shell is movable relative to the lancet guide between a rest position and an actuate position. Movement of the shell between these positions causes a bias element to spring-load the lancet within the lancet guide. Upon the shell being pushed by the user to its actuate position, the lancet is automatically released from the lancet guide and is propelled forward within the lancet guide a sufficient distance such that the skin piercing member pierces the user's skin.
• The lancet is engaged within the lancet guide by any suitable releasing mechanism or catch. The catch holds the lancet within the lancet guide until sufficient spring force is built up with movement of the shell from its rest position to the actuate position, at which point the catch releases the lancet. In a particular embodiment, the catch comprises a cantilevered clip engaged within a recess in the lancet. The clip may be formed integrally with the lancet guide, or attached to the guide, and include an angled engagement surface. A release member may be configured integrally with the shell and may be, for example, a wedge surface that engages the angled engagement surface on the clip to move the clip out of the recess in the lancet.
• The lancet guide serves to retain and guide the lancet. It should be understood that various structural embodiments may be utilized for this purpose. In a particular embodiment, the lancet guide is an open-ended longitudinally extending member, such as a cylinder member, and the lancet is axially slidable within the open-ended member. The bias element may be a spring that extends through a longitudinal end of the lancet guide with one end of the spring engaged against the lancet and the opposite end of the spring engaged with the shell.
• Guide structure, such as tracks or the like, may be provided within the shell along the lancet guide. This guide structure may stabilize movement of the shell relative to the lancet guide.
• The shell may take on any form or shape. In particular embodiments, the shell also defines an outer housing member that is grasped by the user. In alternate embodiments, the shell may be contained within another member, such as a separate housing member.
• In a particular embodiment, the lancet is loaded within the lancet guide and propelled by a spring operably disposed between the lancet and the shell that is moved axially relative to the lancet guide. The spring is designed with a length and spring constant such that, after actuation, the spring retracts the piercing member back into the lancet guide as the spring returns to its equilibrium state even with the shell being held in its actuate position by the user.
• It should be appreciated that the blood sampling device according to the invention may be provided as a stand-alone component, or may be incorporated into any manner of blood testing device. For example, the blood sampling device may be configured as an integral component of any manner of lateral flow assay device. The blood sampling device may be configured at one end of the assay, with the assay housing defining the shell member. In an alternate embodiment, the blood sampling device may be attachable to a blood testing device, for example by a press-fit onto the end of the blood testing device. The shell or housing of the blood sampling device may include a recess or other structure that allows it to attached directly onto the housing of a separate test device, such as a lateral flow assay device. The blood sampling device is not limited to any particular type of blood testing device, and may be incorporated into or attached to any test device that requires a sample of the user's blood.
• Various features and aspects of the present invention are discussed in greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
• A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended drawings, in which:
• FIG. 1 is a perspective view of a blood sampling device according to the invention.
• FIG. 2 is a cross-sectional perspective view of the blood sampling device taken along the lines indicated inFIG. 1
• FIGS. 3A through 3G are sequential operational views of the blood sampling device.
• FIG. 4A is a perspective view of a lateral flow assay device incorporating a blood sampling device in accordance with the invention.
• FIG. 4B is a perspective view of a blood sampling device attachable to a separate lateral flow assay device.
• Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention.
DETAILED DESCRIPTION
• Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
• FIG. 1 illustrates an embodiment of ablood sampling device10 in accordance with aspects of the invention. Thedevice10 is a relatively small, portable, and disposable single-use blood sampling device that is particularly suited for home diagnostic test kits, but it is not limited to such use. Thedevice10 includes ahousing60 of any desired shape and configuration. Thehousing60 is preferably designed so as to be easily grasped and handled with a single hand. Alancet guide22 extends from a forward end of thehousing60, and will be described in greater detail below. Asafety cap34 is provided with thedevice10 and is removed prior to use of the device, as described in greater detail below.
• FIG. 2 is a cross-section view of an embodiment of theblood sampling device10. Alancet12 includes askin piercing member16, such as a trocar, needle, blade, or the like, extending from a forward facinghub14. A circumferential groove orrecess20 is provided at the opposite end of thelancet20. The purpose of thisgroove20 will be explained below.
• Thelancet12 is disposed within theelongated lancet guide22. Thelancet12 is releasably held within thelancet guide22 until actuated, at which time thelancet12 is propelled forward within thelancet guide22 to such an extent that the piercingmember16 pierces the skin of a user. Thelancet guide22 includes a firstlongitudinal end24 that is placed against the user's skin, as particularly illustrated inFIG. 3E. At thelongitudinal end24 of thelancet guide22, a recessedskin engagement area36 is circumscribed by thelongitudinal end structure24, which is pressed against the user's skin. A hub orplate30 defines the end of the recessedskin engagement area36 and includes ahole32 through which theskin piercing member16 extends in the actuated position of thedevice10. Thehole30 is exposed once the user removes thesafety cap34.
• Thelancet guide22 includes an oppositelongitudinal end26 that is disposed within ashell56. Theshell56 may constitute the same structure as thehousing60 illustrated inFIG. 1. In an alternate embodiment, theshell56 may be a separate structure contained within thehousing60. The shape or configuration of theshell56 may vary widely within the scope and spirit of the invention. In general, theshell56 serves to spring-load thelancet12 within thelancet guide22, and to actuate thedevice10, as described in greater detail below.
• In operation, theshell56 is movable or slidable along thelancet guide22 between a rest position (FIG. 3B) and an actuate position (FIG. 3E). Movement of theshell56 between these positions causes abias element38 to spring-load thelancet12 within thelancet guide22. In the illustrated embodiments, thebias element38 is aspring40, but may be a spring washer, resilient material, or any other suitable biasing element. Thespring40 includes afirst end42 that is retained or secured to theshell56 by any conventional means, including a retainingclip62 as illustrated in the figures. Theopposite end44 of thespring40 is disposed against the back end of thelancet12, and may be attached to a hub or other structure on thelancet12.
• Thelancet12 is releasably engaged within thelancet guide22 by any suitable releasing mechanism or catch46. Thecatch46 holds thelancet12 within thelancet guide22 until sufficient spring force is built up with movement of theshell56 from its rest position to its actuate position. At the actuate position, thecatch46 automatically releases thelancet12, which is propelled forward within thelancet guide22. In the illustrated embodiment, thecatch46 is defined by cantilevered arms or clips48 that are engaged within therecess20 in thelancet12. The cantilevered clips48 include anengagement head50 at the end thereof. The cantilevered clips48 are configured with thelancet guide22, and may be defined by slits in the side wall of thelancet guide22. In an alternate embodiment, the cantilevered clips48 may be separate members that are attached to thelancet guide22. Acomplimentary release member52 is configured with theshell56 to engage thecatch46 at the actuate position of theshell56. In the illustrated embodiment, therelease member52 is defined by a relatively simple block that may include anangled wedge surface54. As theshell56 is advanced forward relative to thelancet guide22, therelease member52 will contact theengagement head50 of the cantilevered clips48. Further advancement of theshell56 causes the wedge surfaces54 to force the cantilevered clips48 radially outward to such an extent that the engagement heads50 move out of therecess20 in thelancet guide12.
• Theshell56 may also include any manner ofguide structure58 along any portion of the length of thelancet guide22. Thisguide structure58 may include track members or the like to help ensure relatively smooth sliding movement between theshell56 and thelancet guide22.
• FIGS. 3A through 3G are sequential operational views of the embodiment of theblood sampling device10 illustrated in the figures. Referring toFIG. 3A, theshell56 is illustrated in its rest position relative to thelancet guide22. Thesafety cap34 is illustrated as being removed from thehub30 so as to expose thehole32.Safety cap34 may be a member that is integrally molded with thelancet guide22 or thehub30 and is easily broken off prior to use of thedevice10. In an alternate embodiment, thesafety cap34 may be a tubular member that extends through thelancet guide22 and is attached tolancet12 or to the piercingmember16. In this embodiment, any manner of structure, such asblock member49 inFIG. 3D, may be used to prevent movement of thelancet guide22 andlancet12 when removing thesafety cap34. It should be appreciated that any number of devices may function as asafety cap34, including a removable seal, plug, and so forth.
• FIG. 3B illustrates thedevice10 in its initial position adjacent to theskin35 of a user, for example by the user simply grasping the shell56 (which may also constitute thehousing60 illustrated inFIG. 1) and moving the device towards their finger or an alternate test site.
• FIG. 3C illustrates thedevice10 as thelancet guide22 is initially placed against theskin35 of the user. The recessedskin engagement area36 is circumscribed by theend24 of thelancet guide22, and the user'sskin35 is thus forced to bulge inward into the recessedskin engagement area36 towards theplate30. At this point, thelancet guide22 remains stationary relative to the patient'sskin35 during further actuation of thedevice10.
• FIG. 3D illustrates theshell56 being advanced from its rest position ofFIG. 3C towards its actuate position. As theshell56 is advanced, it slides relative to thelancet guide22 while thelancet12 is retained in its axial position relative to thelancet guide22 by engagement of thehead50 of the cantilevered clips48 within therecess20 defined in thelancet12. Still referring toFIG. 3D, axial movement of theshell56 towards its actuate position results in thespring40 being compressed between the retainingclip42 and the back surface of thelancet12, thereby spring-loading thelancet12 within thelancet guide22.
• FIG. 3E illustrates theshell56 at its actuate position relative to thelancet guide22. At this position, therelease members52 that are configured on theshell56 are moved into contact against the engagement heads50. The wedge surfaces54 of therelease member52 contact against complimentary surfaces of the engagement heads50 and thus cause the heads and cantileveredarms48 to spread radially outward until theheads50 are moved radially out of thegroove20 in thelancet12. At this point, thelancet12 is released and propelled forward within thelancet guide22, as particularly illustrated inFIG. 3F.
• Referring toFIG. 3F, thelancet guide20 is propelled forward by thespring40 to such an extent that theskin piercing member16 extends through thehole32 in theplate30 and pierces the user'sskin35 within the recessedskin engagement area36. Thespring40 is designed so as to have a length and spring constant such that the spring is in an overextended condition at the actuate position of theshell56 illustrated inFIG. 3F. The spring will thus retract to an equilibrium position and withdraw thelancet20 back into the lancet guide22 a sufficient distance so that theskin piercing member16 is withdrawn from the user'sskin35 even if theshell56 is maintained by the user in its actuate position. In other words, the piercingmember16 does not remain penetrated into the user'sskin35 after thelancet12 is triggered, but is automatically withdrawn from the user's skin with no further action by the user.
• FIG. 3G illustrates thedevice10 after it has been actuated and particularly illustrates the position of the piercingmember16 withdrawn back into thelancet guide22 through thehole32. At this point, the user simply moves theshell56 away from theskin35 andblood37 is free to flow from the penetration site.
• Theblood sampling device10 according to the invention may be provided to consumers as a stand alone device, such as the device illustrated inFIG. 1. However, it should also be appreciated that thesampling device10 may be incorporated into an actual blood testing device. For example, theblood sampling device10 may be configured as an integral component of any manner of construction of conventional blood testing devices. Referring toFIG. 4A for example, a lateralflow assay device70 is illustrated that incorporates theblood sampling device10 according to the invention as an integral component. Lateral flow assay devices are known by those skilled in the art and various embodiments of such devices are commercially available. In general, thelateral flow assay70 includes a housing in which is disposed anassay strip72. In certain embodiments, theassay strip72 is configured for detection of specific antibodies in human serum or whole blood samples. Theassay strip72 works on the principle of binding the specific antibodies to a broadly reactive antigen carried by theassay strip72. In the embodiment illustrated inFIG. 4A, the housing of theassay70 includes anelongated portion64 of the same housing that constitutes theshell56 for theblood sampling device10. A sample well66 is provided in theextended housing portion64 into which a blood sample is deposited by, for example, a capillary tube. Awindow68 is provided in thehousing64 so that the user may view a visible indication of the test results on theassay strip72.
• In the embodiment depicted inFIG. 4B, theblood sampling device10 is a separate component from thelateral flow assay70, but is configured to be easily attached to theassay70. For example, the housing of thesampling device10 may include a recess in an end of the housing that is sized to allow the sampling device to be press fitted onto an end of theassay70, as depicted inFIG. 4B. In an alternate embodiment, the recess may be incorporated in theassay70 and thehousing60 of thesampling device10 has a size so as to be pressed into the recess. It should be appreciated that any suitable engaging structure may be utilized for this purpose. Alternatively, an adhesive, hook-and-loop, or other attaching device may be used.
• It should be appreciated that the particular type oflateral flow assay70 or other blood sampling device, or principle of operation, is not particularly relevant to the scope of the invention. The invention includes any blood testing device that incorporates the unique sampling device according to the invention as an integral component or separate but attachable component.
• It should be appreciated by those skilled in the art that various modifications and variations can be made to the embodiments of the invention illustrated or described herein without departing from the scope and spirit of the invention.

Claims (21)

1. A blood sampling device, comprising:

a lancet having a skin piercing member disposed at an end thereof;

an elongated lancet guide, said lancet disposed within and axially movable relative to said lancet guide;

a shell, said lancet guide disposed at least partially within said shell with a first longitudinal end of said lancet guide extending from said shell and placed against a user's skin in operation of said sampling device, said shell axially movable relative to said lancet guide from a rest position to an actuate position;

a bias element disposed between said lancet and a stop on said shell;

a releasable catch configured on said lancet guide, said catch engaged with said lancet in a rest position of said lancet, and a release member configured on said shell so as to contact and release said catch in said actuate position of shell; and

wherein in use of said device, forced movement of said shell relative to said lancet guide loads said bias element against said lancet until said release member contacts and releases said catch at said actuate position of said shell such that said lancet is propelled by said bias element through said lancet guide.

2. The blood sampling device as inclaim 1, wherein said lancet guide is an open-ended longitudinally extending member, said bias element extending through a second longitudinal end of said lancet guide and disposed against said lancet.

3. The blood sampling device as inclaim 2, wherein said shell comprises guide tracks along said lancet guide.

4. The blood sampling device as inclaim 1, wherein said shell defines an outer housing of said device and has a shape and configuration so as to be grasped by a user.

5. The blood sampling device as inclaim 1, wherein said catch comprises a cantilevered clip engaged within a recess in said lancet.

6. The blood sampling device as inclaim 5, wherein said clip comprises an angled engagement surface, and said release member comprises a wedge surface that engages said angled engagement surface on said clip to move said clip out of said recess in said lancet.

7. The blood sampling device as inclaim 1, further comprising a safety cap attached to said first longitudinal end of said lancet guide.

8. The blood sampling device as inclaim 1, wherein said bias element comprises a spring having an end attached to said lancet.

9. The blood sampling device as inclaim 8, wherein said spring comprises a length and spring constant such that said piercing member is withdrawn back into said lancet guide after actuation with said shell at said actuate position.

10. The blood sampling device as inclaim 1, wherein said lancet guide comprises a recessed skin engagement area at said first longitudinal end thereof.

11. The blood sampling device as inclaim 1, further comprising a blood testing device contained within said housing.

12. The blood sampling device as inclaim 11, wherein said blood testing device comprises a lateral flow assay strip.

13. A blood sampling device, comprising:

a lancet having a skin piercing member disposed at an end thereof;

an elongated lancet guide, said lancet releasably engaged with said lancet guide, said lancet guide remaining stationary in use of said device;

a shell axially movable relative to said lancet guide between a rest position and an actuate position, said lancet being spring loaded within said lancet guide with movement of said shell from said rest position to said actuate position; and

said lancet automatically releasing from said lancet guide at said actuate position of said shell.

14. The blood sampling device as inclaim 13, wherein said shell defines an outer housing of said device having a configuration so as to be grasped by a user.

15. The blood sampling device as inclaim 13, further comprising a releasable catch operably disposed between said lancet and said lancet guide, said catch releasing said lancet at said actuate position of said shell.

16. The blood sampling device as inclaim 13, further comprising a spring operably disposed between said lancet and said shell to load said lancet within said lancet guide movement of said shell.

17. The blood sampling device as inclaim 13, wherein said lancet guide comprises a recessed skin engagement area at a first longitudinal end thereof.

18. The blood sampling device as inclaim 13, further comprising a blood testing device configured with said housing.

19. The blood sampling device as inclaim 18, wherein said blood testing device comprises a lateral flow assay strip.

20. The blood sampling device as inclaim 18, wherein said blood testing device is contained within said housing. comprises engagement structure configured to allow attachment of said device to a blood testing device.

21. The blood sampling device as inclaim 20, wherein said blood sampling device is attachable to said housing.

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